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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>Appendices and Supporting Data</title>
      <link>https://trid.trb.org/View/2567120</link>
      <description><![CDATA[This report presents appendices and supporting data for Research Project 913-1F entitled Development of an Absolute Calibration System for Nondestructive Testing Devices.]]></description>
      <pubDate>Sat, 06 Sep 2025 16:36:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2567120</guid>
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      <title>User’s Manual to Computer Program Calibrat: A Program for Calibration of Nondestructive Testing Devices</title>
      <link>https://trid.trb.org/View/2567119</link>
      <description><![CDATA[The Falling Weight Deflectometer (FWD) and Dynaflect devices are presently being used by highway agencies. The primary function of the FWD and Dynaflect devices is to measure a deflection basin due to a load imparted to the pavement. Deflection basins measured in the field are used in backcalculating modulus profiles of pavement sections. As such, it is critical to determine the deflection basins in the field with great accuracy. Velocity transducers (also called geophones) are used to determine the deflections, and load cells are utilized to measure applied load. It has become increasingly important in recent years to be able to evaluate the performance of the deflection and load sensors of the FWD or the Dynaflect devices. It has been shown that a small error in the deflection measured in the field may yield significantly erroneous modulus values. As such, a very reliable method for evaluating the accuracy of the sensors used for determining these deflections is necessary. If geophones are used to determine deflections, the algorithm developed for calculating deflection also becomes important. A geophone measures the so-called "raw" particle velocity of the pavement surface directly underneath it. Therefore, the methodology and algorithm employed to obtain the "actual" displacement must be carefully considered. Errors in the load cell measurements are not as important, but should be avoided for reliable results. This report contains a user's manual for a computer program called CALIBRAT. The program has been developed to control the acquisition and digitization of sensor's signals, to reduce the collected data, and to present the data. The program is coded for an IBM-PC Compatible equipment with DT 2825 Analog-to-Digital board manufactured by Data Translation, Inc. The program is written in FORTRAN and compiled with MICROSOFT FORTRAN (4.1) Compiler.]]></description>
      <pubDate>Sat, 06 Sep 2025 16:36:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2567119</guid>
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    <item>
      <title>Comprehensive Evaluation of Five Sensors Used for Pavement Monitoring</title>
      <link>https://trid.trb.org/View/2567118</link>
      <description><![CDATA[The Falling Weight Deflectometer (FWD) and Dynaflect devices are presently being used by highway agencies. The primary function of the FWD and Dynaflect devices is to measure a deflection basin due to a load imparted to the pavement. Deflection basins measured in the field are used in backcalculating modulus profiles of pavement sections. As such, it is critical to determine the deflection basins in the field with great accuracy. Velocity transducers (also called geophones) are used to determine the deflections, and load cells are utilized to measure applied load. It has become increasingly important in recent years to be able to evaluate the performance of the deflection and load sensors of the FWD or the Dynaflect devices. It has been shown that a small error in the deflections measured in the field may yield significantly erroneous modulus values. As such, a very reliable method for evaluating the accuracy of the sensors used for determining these deflections is necessary. If geophones are used to determine deflections, the algorithm developed for calculating deflection will also become important. A geophone measures the so-called "raw" particle velocity of the pavement surface directly underneath it. Therefore, the methodology and algorithm employed to obtain the "actual" displacement must be carefully considered. Errors in the load cell measurements are not as important but should be avoided for reliable results. In this report, the results of an all-around evaluation of five sensors which are commonly used in pavement engineering area are presented. These sensors are: an accelerometer, a LVDT, a proximeter, a geophone and a laser optocator. In the evaluation process, factors such as, cost, accuracy, precision, field-worthiness and ease of mounting were considered. It was found that the geophones are the most suitable sensors amongst the five sensors evaluated.]]></description>
      <pubDate>Sat, 06 Sep 2025 16:36:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2567118</guid>
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    <item>
      <title>Layer Equivalency Factors and Deformation Characteristics of Flexible Pavements Test Data</title>
      <link>https://trid.trb.org/View/2561667</link>
      <description><![CDATA[This document is a supplement to Research Report 284-3, "Layer Equivalency Factors and Deformation Characteristics of Flexible Pavements." It contains the collection of graphs of the pressuremeter test and the corresponding regression curves for the hyperbolic stress-strain model performed during the course of the study reported in Research Report 284-3.]]></description>
      <pubDate>Mon, 21 Jul 2025 16:19:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2561667</guid>
    </item>
    <item>
      <title>Layer Equivalency Factors and Deformation Characteristics of Flexible Pavements</title>
      <link>https://trid.trb.org/View/2561668</link>
      <description><![CDATA[In this report, a method is developed for determining the equivalent thicknesses for different base courses, which will give the same pavement life expectancy. This study shows how the layer equivalents can be obtained from Texas Triaxial tests or from pavement pressuremeter tests or from Dynaflect tests. The procedures were developed after testing 11 pavement sections having four different types of base courses and subbase courses in the Beaumont District (District 20) in Southeastern Texas. Taking the sand and oyster shell base course as reference (layer equivalent of 1), it was found that the lime treated crushed sandstone had a layer equivalent of 0.68, the iron ore 1.17, and the select sand 1.29. This study permitted moduli of deformation to be obtained from the pressuremeter test, the Texas Triaxial test and the Dynaflect test coupled with the Russian equation. Comparisons between the various moduli are presented. This study used the cyclic pressuremeter test to determine the stress and strain level dependency of soil moduli and permanent deformation characteristics of the layers. This report includes the presentation of a procedure to determine the layer equivalents of base courses on the basis of Texas Triaxial tests. Examples of calculations are included.]]></description>
      <pubDate>Mon, 21 Jul 2025 16:19:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2561668</guid>
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    <item>
      <title>Preliminary Evaluation of Fly Ash Test Sites Using Static and Dynamic Deflection Systems</title>
      <link>https://trid.trb.org/View/2549164</link>
      <description><![CDATA[This report summarizes the evaluation of six experimental fly ash stabilized base and subgrade test sites on selected Texas Highways. The sites, each consisting of several test sections, were analyzed using the dual parametric approach on field measured Dynaflect and Benkleman Beam deflection data. Five out of six sites exhibited significant increases in structural support capability with time. Strong relationships were found in variations of lime-fly ash percentages to changes in dual parametric results. Variations in fly ash percentages seemed to dominate the changes in parameters more than variations in lime content. The study corroborates the viability of fly ash as a partial replacement for lime in stabilized bases and subgrades.]]></description>
      <pubDate>Mon, 23 Jun 2025 18:39:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2549164</guid>
    </item>
    <item>
      <title>Literature review of the traffic speed deflectometer : an overview with an emphasis on implementation in pavement management systems</title>
      <link>https://trid.trb.org/View/2491296</link>
      <description><![CDATA[Deterioration models and planning of road maintenance have been founded on deflection measurements since road research begun in the early twentieth century. Until the beginning of the twenty-first century the methods of collecting data were slow, and road network measurements were a challenge. The Traffic Speed Deflectometer (TSD) is the first commercially available fast deflection measurement system, which premiered with a first large test in 2001. The TSD attracted considerableinternational interest early on, and at present twenty-one vehicles have been produced.   The main objective of the project of which the present literature review is a part, is to develop an index to describe the structural condition on the paved parts of the Swedish and finnish state-owned road networks. The plan is to use both the results from conventional road surface measurements and the results from dedicated TSD measurements as input for the future index. The index should be suitable for both the planning of maintenance and the long-term monitoring of the structural condition of the road network.  The literature review is, for practical purposes, focused on the use of the TSD and how TSD data can be used in a Pavement Management System (PMS), as these are the main objectives with the project. However, the literature on the TSD isn't more extensive than most of the other aspects (repeatability, reproducibility, validation, calibration, etc.) can also be covered, albeit more briefly.]]></description>
      <pubDate>Fri, 17 Jan 2025 15:18:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2491296</guid>
    </item>
    <item>
      <title>Effect of Environmental Factors and Loading Position on Dynaflect Deflections in Rigid Pavements</title>
      <link>https://trid.trb.org/View/2440039</link>
      <description><![CDATA[In this report, several of the factors that affect Dynaflect deflections in rigid pavements are analyzed. Findings from this study are incorporated into a recommended procedure for the use of the Dynaflect. The Slab-49 program is used to simulate voids of various sizes under a continuously reinforced concrete pavement. The effect of a placement error in the deflection measurement device is also studied. Distances from the pavement edge at which the Dynaflect should be placed are recommended for both materials characterization and void detection. A discussion about the effect of environmental factors on deflections in rigid pavements is also presented. Statistical analysis is considered for determining the required number of Dynaflect deflections to obtain representative results. Finally, the results from this report are combined into a recommended procedure for Dynaflect deflection measurements, which, it is hoped, will result in improvements to the determination of input data for rigid pavement overlay design computer programs.]]></description>
      <pubDate>Sat, 12 Oct 2024 16:11:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2440039</guid>
    </item>
    <item>
      <title>MESAS Aus- und Bewertung Stufe 1
</title>
      <link>https://trid.trb.org/View/2425021</link>
      <description><![CDATA[MESAS ist ein multifunktionales Erfassungssystem zur Substanzbewertung und zum Aufbau von Straßen und bezeichnet des Weiteren ein umfassendes, wissenschaftliches Projekt. MESAS soll Eingangsgrößen für die Substanzbewertung auf Netzebene zerstörungsfrei liefern und das Erhaltungsmanagement, auch Pavement-Management, unterstützen. Durch MESAS wird es möglich sein, die durch die Zustandserfassung und -bewertung (ZEB) erfassten Oberflächenmerkmale mit strukturellen Zustandsdaten zu ergänzen. Im Fall von MESAS bezieht sich dies konkret auf die Tragfähigkeitsmessungen sowie die Messungen mit dem Georadarsystem. Zur detaillierten Überprüfung, wie sich Oberflächendaten mit strukturellen Zustandsdaten sinnvoll miteinander kombinieren lassen, ist MESAS auch mit Messsystemen ausgestattet, die synchron den Oberflächenzustand erfassen. MESAS basiert auf dem Traffic Speed Deflectometer (TSD). Die Möglichkeiten der Einbindung der mit dem TSD erfassten Daten in Pavement-Management-Systeme (PMS) werden weltweit diskutiert. Da es sich um ein sehr junges Messverfahren handelt, gibt es eine Reihe von Ansätzen zur Nutzung der Daten, allerdings noch keine oder kaum etablierte Prozesse. Des Weiteren werden auch noch Punkte zum Betrieb, zur Kalibrierung und zur Messdatenverarbeitung diskutiert. Das BASt-eigene Messfahrzeug MESAS ist eines der wenigen, wenn nicht sogar das einzige TSD, das vollständig für die Forschung genutzt werden kann und zugleich in eine starke Infrastruktur eingebunden ist, die es erlaubt, großmaßstäblich, das heißt auf Netzebene, Daten zu sammeln. Die Einbindung von MESAS in das Erhaltungsmanagement, beziehungsweise die Prüfung der Möglichkeiten und Grenzen der Einbindung, ist in einem zweistufigen Projekt geplant. Die Bearbeitung der Stufe 1 untergliedert sich in die Schwerpunkte Einsatzbedingungen und Bewertung. ABSTRACT IN ENGLISH: MESAS is a multifunctional recording system for the substance assessment of road constructions and also refers to an extensive scientific project. The MESAS measurement vehicle owned by BASt is one of the few, if not the only Traffic Speed Deflectometer (TSD) that can be fully utilised for research and is simultaneously integrated into a strong infrastructure that allows data to be collected on a large scale, i.e. at network level. The integration of MESAS into maintenance management, or rather the examination of its possibilities and limitations, is planned in a two-stage project. Stage 1 is subdivided into the key areas of operating conditions and evaluation.
]]></description>
      <pubDate>Mon, 02 Sep 2024 11:17:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2425021</guid>
    </item>
    <item>
      <title>Quality Control of Full-Depth Reclamation (FDR): A Case Study</title>
      <link>https://trid.trb.org/View/2377934</link>
      <description><![CDATA[Although Full-Depth Reclamation (FDR) with stabilization of pavements has been known for nearly 50 years, this process is not widely used, as its potential (i.e. reduction in natural resources consumption, transportation, waste, emissions, energy and cost) is underestimated. This is due to a lack of knowledge about pavement design and the absence of quality control methods and on-site tests to monitor the hardening progress of these recycled materials. In this Quebec study, it is proposed to evaluate the applicability of devises that are sufficiently accurate, easy to transport and use for quality control of theses recycled materials. The Dynamic Cone Penetrometer (DCP) provides information on the thickness, strength and variability of unstabilized layers. Through correlations, it is possible to calculate the resilient modulus (M,) and the California Bearing Ratio (CBR) of layers; useful for pavement design. On the stabilized layer, it is necessary to use a Lightweight Deflectometer (LWD), to evaluate the surface elastic modulus (Elwd) of the pavement and monitor the hardening or strength gain of the layer. Overall, this study has shown that DCP and LWD devises are highly effective in assessing FDR characteristics, but some limitations were found. Some guidelines for their use are presented.]]></description>
      <pubDate>Thu, 13 Jun 2024 09:46:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2377934</guid>
    </item>
    <item>
      <title>Litteraturgenomgång rörande Traffic Speed Deflectometer : en översikt med tonvikt på implementering i Pavement Management System</title>
      <link>https://trid.trb.org/View/2389087</link>
      <description><![CDATA[Deterioration models and planning of road maintenance have been founded on deflection measurements since road research begun in the early twentieth century. Until the beginning of the twenty-first century the methods of collecting data were slow, and road network measurements were a challenge. The Traffic Speed Deflectometer (TSD) is the first commercially available fast deflection measurement system, which premiered with a first large test in 2001. The TSD attracted great international interest early on, and at present nineteen vehicles have been produced. The main objective of the project of which the present literature review is a part, is to develop an index to describe the structural condition on the paved parts of the Swedish and finnish state-owned road networks. The plan is to use both the results from conventional road surface measurements and the results from dedicated TSD measurements as input for the future index. The index should be suitable for both the planning of maintenance and the long-term monitoring of the structural condition of the road network. The literature review is, for practical purposes, focused on the use of the TSD and how TSD data can be used in a Pavement Management System (PMS), as these are the main objectives with the project. However, the literature on the TSD isn't more extensive than most of the other aspects (repeatability, reproducibility, validation, calibration, etc.) can also be covered, albeit more briefly.]]></description>
      <pubDate>Mon, 10 Jun 2024 14:06:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389087</guid>
    </item>
    <item>
      <title>Evaluation of Recycled Bituminous Pavement</title>
      <link>https://trid.trb.org/View/2317590</link>
      <description><![CDATA[The study was initiated to evaluate the performance of recycled bituminous material as the base course of reconstructed county roads. The cold recycling process has been used in recent years by Elkhart County, Indiana to upgrade sections of distressed roads. The evaluation is based on a comparison of the material from laboratory extraction and gradation tests and the pavement structure from Dynaflect tests before and after treatment. Dynaflect tests and PCA Roadmeter tests were also run six, eight, eleven, and seventeen months after construction to evaluate the performance of the recycled pavement under traffic. Gradation results indicate that the before and after treatment material is very similar. An excess of asphalt was present in the treated material. Also, the gradations both before and after were quite dense and both indicated a deficiency of material greater than 1/2". Considerable variability was noticed relative to gradation and asphalt content indicating that the processed material was not homogeneous. The Dynaflect parameters developed from tests on the treated material verified the lack of uniformity. A simple comparative cost analysis clearly shows the cold recycling process is significantly less expensive than the hot mixed, hot placed material. In this study the cost in place of a plant mixed base such as Indiana's HAC #5 Base was three times more than the recycled material.]]></description>
      <pubDate>Sat, 06 Jan 2024 11:10:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2317590</guid>
    </item>
    <item>
      <title>Manitoba’s New Models for Correcting FWD Deflections to Standard Temperature for Pavement Design and Analysis</title>
      <link>https://trid.trb.org/View/2071814</link>
      <description><![CDATA[The load carrying capacities, relative strengths and the required overlays of existing pavements are generally determined using the measured surface deflection values. The Falling Weight Deflectometer (FWD) is the most common device for measuring pavement surface deflections. In all general pavement design and analysis, the measured deflection values are corrected to a standard effective pavement temperature. However, the effective pavement temperatures have been typically measured using an oil, poured into the predrilled holes on pavement surface. Such temperatures may not truly reflect the temperatures of pavement layers or materials. In addition, highway agencies typically apply a correction factor to central deflection only or apply a single temperature correction factor to all geophone deflections at a test point. These could result in some errors because of not accounting for the effect of temperature or lower sensitivity of farther (from FWD plate) geophone deflections to changes in temperature. Some jurisdictions, like Manitoba, also adopted the Benkelman Beam Rebound (BBR) deflections temperature correction models for FWD deflections. This may not be appropriate because of two different mechanisms of deflection measurement.  Manitoba Transportation and Infrastructure (MTI) has collected the temperature data from several thermistors to develop a new model for estimating the effective pavement temperature. The measured FWD deflections and temperatures at different sites were then used to develop a separate temperature correction model for each geophone deflection. The results and analyses showed that the estimated pavement effective temperatures using the new interim model are higher, with a smaller difference between the surface and effective temperatures, than that estimated using the currently used model. The correction model is different for each geophone deflection with a progressively smaller regression coefficient for geophones away (up to 900mm) from the centre of the FWD load plate. The new interim models also provide a reduction in the required overlay thickness.]]></description>
      <pubDate>Tue, 29 Nov 2022 14:16:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2071814</guid>
    </item>
    <item>
      <title>Pavement Deflection Data at the Long-Term Monitoring Sites in Idaho for Structural Performance</title>
      <link>https://trid.trb.org/View/2005662</link>
      <description><![CDATA[This final report presents the results of the evaluation of the Dynaflect deflections measured on asphalt concrete pavements at the Long Term Monitoring sites in Idaho. A brief discussion of cross-slab deflections for portland cement concrete pavements is also presented. The study was intended to seek possible correlations between deflections and surface cracking. A previous report presented the authors' findings for a similar evaluation for the portland cement concrete pavements. This report will provide details about the methodology, a discussion of the results, followed by conclusions and recommendations for future research.]]></description>
      <pubDate>Wed, 21 Sep 2022 16:20:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2005662</guid>
    </item>
    <item>
      <title>Field compaction of thick recycled material layers</title>
      <link>https://trid.trb.org/View/1682682</link>
      <description><![CDATA[Full-depth reclamation techniques present numerous advantages in pavement rehabilitation. Typically, a thick layer of stabilized or unstabilized reclaimed materials is left behind the recycling machine, which is used as the base layer consisting of these latter recycled asphalt pavement material (RAP). The compaction of the thick layer, especially when unstabilized, is particularly critical for adequate performance. In Quebec, the smooth drum compaction is often used to compact the reclaimed materials. Previous studies demonstrated the difficulties associated with the convenient compaction of the reclaimed materials through its entire thickness, especially the presence of a vertical compaction gradient. Sheep or pad foot compactors are two common compaction machines used to ensure good densification during primary compaction of recycled materials. A research project was initiated to document and quantify the effects of compaction conditions and equipment on the response and performance of the reclaimed materials. An experimental embankment of reclaimed materials was built and divided in three sections compacted using different compaction procedures. Sheepsfoot roller, with and without vibration, was used in the first two sections, while the third section was compacted using a vibrating smooth drum roller. The density, stiffness and vertical density gradient were monitored with a nuclear gage, dynamic cone penetrometer and light weight deflectometer tests. Grain-size analysis was also performed on all experimental sections. The use of vibration along with Sheepsfoot roller improved both density and mechanical response of the compacted layer significantly. The penetration and density tests also revealed a significant difference in compaction throughout the thick layer of reclaimed materials. Using the sheepsfoot provided a stiffer base layer, and the smooth drum resulted in a vertical density gradient. Finally, significant differences in the grainsize distribution were found following the compaction when the sheepsfoot compactor was used.]]></description>
      <pubDate>Tue, 04 Feb 2020 14:59:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1682682</guid>
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